Three-loop neutrino masses via new massive gauge bosons from $E_6$ GUT

Understand

We propose an $SU(3)_C\times SU(2)_L \times SU(2)_N \times U(1)_Y$ model arising from $E_6$ grand unified theory.

• We show that the tiny neutrino masses in this model can be generated at the three-loop involving the $SU(2)_N$ gauge bosons.
• With Yukawa couplings around 0.01 or larger and TeV-scale $SU(2)_N$ gauge bosons, we show that the neutrino oscillation data can be explained naturally by presenting a concrete benchmark set of input parameters.
• All new particles are around the TeV scale.